Over the past century, aviation technology has evolved exponentially, from the nible biplanes that contested the skies over France and Flanders in World War I to the modern multi-role stealth fighters coming into service that will define air power for the next half century. World War II demonstrated the tactical and strategic importance of the air arms, where they formed an integral part of the Blitzkrieg and the Allied offensives. The destructive power of modern air forces was nowhere more evident than in the strategic bomber offensives against Germany and Japan where entire cities were laid to waste through aerial bombardment alone, culminating in the dropping of the atomic bombs. Despite its fearsome potential, however, it was only until the 1991 Gulf War when air power could claim to have become a war winning weapon in itself, thanks to advances in technology such as precision weaponry and stealth that gave NATO a considerable lead over its Warsaw Pact adversaries in the final years of the Cold War. These technologies will continue to define airpower into the 21st century where the role of warplanes and helicopters in the modern battlefield will remain undimished, and as aspiring superpowers like China continue to chip away at the West's current lead in aerial warfare.

There are currently 555 entries and data on 831 combat aircraft and helicopters.

The dominance of mass infantry armies reached its apex in World War I, but the massive casualties incurred in fruitless assualts against enemy trenches spurred the development of more maneuverable weapons such as tanks. Although these came too late to influence the outcome of the war, by the outbreak of World War II they had established themselves as leading weapon of land warfare as evidenced by the German Blitzkrieg offensives during 1939-41. But despite the proficiency of the German panzer forces, it was the Allies that led the way in establishing fully motorized armies by the end of the war and into the Cold War. Over the past half century, the armies of the world have increasingly relied on armored vehicles to provide their troops with the mobility needed to excel in the modern battlefield. Meanwhile, the primacy of the tank has remained undiminished, as evidenced by the tank battles fought during the numerous conflicts between Israelis and Arabs in the Middle East and culminating in the 1991 Gulf War. Luckily, the clash of armored titans between NATO and the Warsaw Pact in Central Europe never ccame to be, but the legacy of the Cold War between East and West has continued to influence armored warfare to this day.

The development of the all-big gun battleship in the early part of the 20th Century triggered an arms race that was to shape the development of sea warfare for the next generation. The climax came during the Battle of Jutland in 1916 where the great British and German battlefleets met head on in what remains to this day as the largest surface battle in history. Fears of a resumption of naval building in the aftermath of the war resulted in the Washington Naval Treaty of 1922 that limited the size of the world's great navies as well as the size of their ships. By the outbreak of World War II, developments in naval aviation resulted in the aircraft carrier replacing the battleship as the queen of the seas and nowhere was this more evident than in the Pacific, where the U.S. and Japanese fleets waged the most intense naval campaign of all time. With its massive fleet of carriers, the U.S. emerged from the war replacing the Royal Navy as the most powerful naval force in the world even though its dominance over the seas became increasingly challenged by the Soviet Union in the latter part of the Cold War. However, the dissolution of the U.S.S.R. left the U.S. as the the sole naval superpower, one with a fleet that is larger more powerful than the rest of the world's combined.

There are currently 1,117 entries, data on 215 warship types, and 16,724 individual warships in the registry.